Structural investigation on supercritical carbon dioxide and its mixture with alcohol

✍ Scribed by Takashi Sato; Masaaki Sugiyama; Masakatsu Misawa; Kei Hamada; Keiji Itoh; Kazuhiro Mori; Toshiharu Fukunaga

• Book ID: 104059662
• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 352 KB
• Volume: 147
• Category: Article
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2008.06.017

✦ Synopsis

Small-angle neutron scattering (SANS) experiments were carried out for three different systems, pure CO 2 , CO 2 + methanol (1 mol%) and CO 2 + ethanol (1 mol%), along the isotherm of 311.15 K in their supercritical states. All the SANS profiles were well analyzed with Ornstein-Zernike equation. With addition of the alcohols, the maximum values of the correlation length, ξ, and the scattering intensity at Q = 0, I(0), became larger, and the pressure at which ξ and I(0) became maxima was shifted to be lower. These changes can be explained qualitatively with van der Waals equation of state by regarding CO 2 + alcohol mixture as a system consisting of a single kind of virtual molecules. From this analysis, both the molecular attractive interaction and volume are suggested to be increased in the mixture. These changes were considered to be strongly connected with the increase of solubility and selectivity on entrainer effect.